﻿/***********************************************
 * CodeList.4
 * 文章：C# 中的委托(Delegate)
 * 出处：http://www.tracefact.net/CSharp-Programming/Delegates-and-Events-In-CSharp.aspx
 * 日期：2007-9-20
 * 说明：符合.Net Framework 规范的一个Observer模式实现
 * 作者：张子阳(Jimmy Zhang)
 * ********************************************/

using System;
using System.Collections.Generic;
using System.Text;

namespace Delegate {
	// 热水器
	public class Heater {
		private int temperature;
		public string type = "RealFire 001";		// 添加型号作为演示
		public string area = "China Xian";			// 添加产地作为演示

		public delegate void BoiledEventHandler(Object sender, BoiledEventArgs e);	//声明委托
		public event BoiledEventHandler Boiled;	//声明事件

		// 定义BoiledEventArgs类，传递给Observer所感兴趣的信息
		public class BoiledEventArgs : EventArgs {
			public readonly int temperature;
			public BoiledEventArgs(int temperature) {
				this.temperature = temperature;
			}
		}

		// 可以供继承自 Heater 的类重写，以便继承类拒绝其他对象对它的监视
		protected virtual void OnBolied(BoiledEventArgs e) {
			if (Boiled != null) {	//如果有对象注册
				Boiled(this, e);		//调用所有注册对象的方法
			}
		}
		
		// 烧水。
		public void BoilWater() {
			for (int i = 0; i <= 100; i++) {
				temperature = i;
				if (temperature > 95) {
					BoiledEventArgs e = new BoiledEventArgs(temperature);
					OnBolied(e);
				}
			}
		}
	}

	// 警报器
	public class Alarm {
		public void MakeAlert(Object sender, Heater.BoiledEventArgs e) {
			Heater heater = (Heater)sender;		//这里是不是很熟悉呢？
			//访问 sender 中的公共字段
			Console.WriteLine("Alarm：{0} - {1}: ", heater.area, heater.type);
			Console.WriteLine("Alarm: 嘀嘀嘀，水已经 {0} 度了：", e.temperature);
			Console.WriteLine();
		}

	}

	// 显示器
	public class Display {
		public static void ShowMsg(Object sender, Heater.BoiledEventArgs e) {	//静态方法
			Heater heater = (Heater)sender;
			Console.WriteLine("Display：{0} - {1}: ", heater.area, heater.type);
			Console.WriteLine("Display：水快烧开了，当前温度：{0}度。", e.temperature);
			Console.WriteLine();
		}
	}

	class Program {
		static void Main() {
			Heater heater = new Heater();
			Alarm alarm = new Alarm();

			heater.Boiled += alarm.MakeAlert;	//注册方法
			heater.Boiled += (new Alarm()).MakeAlert;		//给匿名对象注册方法
			heater.Boiled += new Heater.BoiledEventHandler(alarm.MakeAlert);	//也可以这么注册
			heater.Boiled += Display.ShowMsg;		//注册静态方法

			heater.BoilWater();	//烧水，会自动调用注册过对象的方法
		}
	}
}
